Muscular system
Muscular system
Skeletal muscles and their attachments and actions.
114 structures
Upper limb
49Abductor digiti minimi (hand)
Hypothenar — abducts little finger
MuscleAbductor pollicis brevis
Thenar — abducts the thumb
MuscleAbductor pollicis longus
Deep thumb abductor
MuscleAdductor pollicis
Adducts the thumb (Froment sign)
MuscleAnconeus
Assists elbow extension
MuscleBiceps brachii
Chief supinator of the forearm
MuscleBrachialis
Workhorse elbow flexor
MuscleBrachioradialis
"Beer-raising" elbow flexor
MuscleCoracobrachialis
Pierced by musculocutaneous nerve
MuscleDeltoid
Prime arm abductor
MuscleDorsal interossei (hand)
ABduct the fingers (DAB)
MuscleExtensor carpi radialis brevis
Wrist extensor, tennis elbow
MuscleExtensor carpi radialis longus
Extends and abducts the wrist
MuscleExtensor carpi ulnaris
Extends and adducts the wrist
MuscleExtensor digiti minimi
Extends the little finger
MuscleExtensor digitorum
Main finger extensor
MuscleExtensor indicis
Independent index extensor
MuscleExtensor pollicis brevis
Extends the thumb MCP
MuscleExtensor pollicis longus
Extends the thumb IP joint
MuscleFlexor carpi radialis
Flexes and abducts the wrist
MuscleFlexor carpi ulnaris
Flexes and adducts the wrist
MuscleFlexor digiti minimi brevis (hand)
Hypothenar — flexes little finger
MuscleFlexor digitorum profundus
Only muscle flexing the DIP joints
MuscleFlexor digitorum superficialis
Flexes the PIP joints
MuscleFlexor pollicis brevis
Thenar — flexes the thumb
MuscleFlexor pollicis longus
Flexes the thumb IP joint
MuscleInfraspinatus
Rotator cuff — lateral rotation
MuscleLatissimus dorsi
Broad climbing/swimming muscle
MuscleLevator scapulae
Elevates the scapula
MuscleLumbricals (hand)
Flex MCP, extend IP joints
MuscleOpponens digiti minimi
Hypothenar — cups the palm
MuscleOpponens pollicis
Thenar — opposes the thumb
MusclePalmar interossei
ADduct the fingers (PAD)
MusclePalmaris longus
Absent in ~10–15% of people
MusclePectoralis major
Anterior chest wall, arm adductor
MusclePectoralis minor
Anchors the scapula, surgical landmark
MusclePronator quadratus
Deep primary pronator
MusclePronator teres
Pronates the forearm
MuscleRhomboid major
Scapular retractor
MuscleRhomboid minor
Scapular retractor (superior)
MuscleSerratus anterior
Boxer's muscle
MuscleSubclavius
Protects subclavian vessels
MuscleSubscapularis
Rotator cuff — medial rotation
MuscleSupinator
Supinates the extended forearm
MuscleSupraspinatus
Rotator cuff — initiates abduction
MuscleTeres major
"Lat's little helper"
MuscleTeres minor
Rotator cuff — lateral rotation
MuscleTrapezius
Superficial back, scapular stabiliser
MuscleTriceps brachii
Chief elbow extensor
MuscleLower limb
38Adductor brevis
Deep adductor
MuscleAdductor longus
Adducts the thigh
MuscleAdductor magnus
Two-part composite adductor
MuscleBiceps femoris
Lateral hamstring
MuscleExtensor digitorum longus
Extends the lateral four toes
MuscleExtensor hallucis longus
Extends the big toe
MuscleFibularis brevis
Everts the foot
MuscleFibularis longus
Everts the foot, supports arches
MuscleFibularis tertius
Dorsiflexes and everts (variable)
MuscleFlexor digitorum longus
Flexes the lateral four toes
MuscleFlexor hallucis longus
Flexes the big toe, push-off
MuscleGastrocnemius
Superficial calf, crosses the knee
MuscleGluteus maximus
Powerful hip extensor
MuscleGluteus medius
Hip abductor and pelvic stabiliser
MuscleGluteus minimus
Deep hip abductor
MuscleGracilis
Medial thigh, crosses the knee
MuscleIliacus
Hip flexor (with psoas)
MuscleInferior gemellus
Lateral rotator (with obturator internus)
MuscleObturator externus
Lateral rotator (medial thigh group)
MuscleObturator internus
Lateral rotator of the hip
MusclePectineus
Flexes and adducts the hip
MusclePiriformis
Key landmark of the gluteal region
MusclePlantaris
Vestigial calf muscle
MusclePopliteus
"Unlocks" the knee
MusclePsoas major
Chief hip flexor
MuscleQuadratus femoris
Strong lateral rotator
MuscleRectus femoris
Quadriceps — crosses hip and knee
MuscleSartorius
Longest muscle in the body
MuscleSemimembranosus
Medial hamstring, broad tendon
MuscleSemitendinosus
Medial hamstring, long tendon
MuscleSoleus
Calf "peripheral heart"
MuscleSuperior gemellus
Lateral rotator (with obturator internus)
MuscleTensor fasciae latae
Tenses the IT tract
MuscleTibialis anterior
Chief dorsiflexor
MuscleTibialis posterior
Chief invertor, supports arch
MuscleVastus intermedius
Deep quadriceps head
MuscleVastus lateralis
Largest quadriceps head
MuscleVastus medialis
Stabilises the patella (VMO)
MuscleTrunk
11Diaphragm
Principal muscle of respiration
MuscleErector spinae
Iliocostalis, longissimus, spinalis
MuscleExternal intercostals
Elevate ribs (inspiration)
MuscleExternal oblique
Outermost flat abdominal muscle
MuscleInternal intercostals
Depress ribs (expiration)
MuscleInternal oblique
Middle flat abdominal muscle
MuscleMultifidus
Deep segmental stabiliser
MuscleQuadratus lumborum
Posterior abdominal wall
MuscleRectus abdominis
The 'six-pack'
MuscleSplenius capitis
Extends and rotates the head
MuscleTransversus abdominis
Deepest flat abdominal muscle
MuscleHead & neck
16Anterior scalene
Key neck landmark
MuscleBuccinator
Muscle of the cheek
MuscleDigastric
Two-bellied suprahyoid muscle
MuscleLateral pterygoid
Protrudes the jaw, opens the mouth
MuscleMasseter
Strongest muscle of mastication
MuscleMedial pterygoid
Elevates the jaw
MuscleMylohyoid
Floor of the mouth
MuscleOccipitofrontalis
Raises the eyebrows
MuscleOmohyoid
Infrahyoid strap muscle
MuscleOrbicularis oculi
Closes the eyelids
MuscleOrbicularis oris
Closes and purses the lips
MusclePlatysma
Muscle of facial expression (neck)
MuscleSternocleidomastoid
Key neck landmark
MuscleSternohyoid
Infrahyoid strap muscle
MuscleTemporalis
Elevates and retracts the jaw
MuscleZygomaticus major
Smiling muscle
Muscle